Jesse has been working to improve his cardiovascular fitness. Which of the following is the BEST objective measure of his progress? 1. He feels proud of what he has accomplished so far.

2. He has lost enough weight that he needs to buy pants with a smaller waist.

3. He can run a mile five minutes faster than he could when he started.

4. He seldom has problems with muscles strain or joint pain nowadays.

As you sit in the library with your friend studying for your weekly quiz on the integumentary system, you come upon an article about the hazards of prolonged exposure to the sun's rays. your curious nature leads you to research the subject further. you're fascinated to learn that minimal exposure to the sun allows you skin to manufacture vitamin d, which is important to maintain homeostasis. you also read that although sunscreen can protect you from the ultraviolet (uv) rays of the sun, some medications can actually increase a person's sensitivity to the sunlight.